package dbAccess

import (
	"context"
	"time"

	"git.fjla.uk/owlboard/timetable-mgr/log"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo/options"
	"go.uber.org/zap"
)

// CAUTION: Drops the collection named in collectionName
func DropCollection(collectionName string) error {
	log.Info("Dropping collection", zap.String("Collection Name", collectionName))
	database := MongoClient.Database(DatabaseName)
	collection := database.Collection(collectionName)

	err := collection.Drop(context.Background())
	if err != nil {
		log.Error("Error dropping collection", zap.String("Collection Name", collectionName), zap.Error(err))
		return err
	}

	return nil
}

// Checks the update time (unix timestamp) of the collection named in collectionName, uses 'type: collection' entries in the meta collection
func CheckUpdateTime(collectionName string) (int64, error) {
	database := MongoClient.Database(DatabaseName)
	collection := database.Collection(MetaCollection)
	filter := bson.D{
		{Key: "target", Value: collectionName},
		{Key: "type", Value: "collection"},
	}
	var result struct {
		Updated int64 `bson:"updated"`
	}
	err := collection.FindOne(context.Background(), filter).Decode(&result)
	if err != nil {
		return 0, err
	}
	return result.Updated, nil
}

// Sets a new update time (unix timestamp) of the collection named in collectionName.  The update time is calculated within the function.
func SetUpdateTime(collectionName string) error {
	log.Info("Setting update time", zap.String("collection", collectionName))
	database := MongoClient.Database(DatabaseName)
	collection := database.Collection("meta")
	options := options.Update().SetUpsert(true)
	updateTime := time.Now().Unix()
	filter := bson.M{
		"target": collectionName,
		"type":   "collection",
	}
	update := bson.M{
		"$set": bson.M{
			"updated":      updateTime,
			"updated_time": time.Now().In(time.UTC),
			"target":       collectionName,
			"type":         "collection",
		},
	}
	_, err := collection.UpdateOne(context.Background(), filter, update, options)

	if err != nil {
		log.Error("Error setting update time", zap.String("collection", collectionName), zap.Error(err))
		return err
	}
	return nil
}